The earthwork sitting on this knoll is a rath, the Irish term for a ringfort, a type of enclosed farmstead typically built between roughly the fifth and twelfth centuries. Thousands survive across Ireland, though many are damaged or overlooked; this one retains a legible, even instructive, outline.

The enclosure is oval to sub-rectangular in plan, measuring about 40 metres north to south and 32 metres east to west, with fairly straight sides and rounded corners rather than the more common smooth oval. What makes it structurally interesting is its layered defences: an inner bank roughly two metres wide and standing about two metres on its outer face, then a wide external fosse, a defensive ditch, some four metres across and a metre deep, and beyond that a smaller outer bank. A probable entrance gap of around two metres opens in the south-west, while a causeway about three metres wide crosses the fosse on the eastern side, suggesting at least two points of access, or possibly one original and one later. Some quarrying has disturbed the south-east quadrant of the interior, which is a common fate for earthworks in agricultural landscapes where stone was needed and the ground was already loosened by centuries of use. The knoll offers good views across the undulating terrain, a consideration that would not have been lost on whoever chose the spot. Glashare Castle sits roughly 100 metres to the south-south-east, and a separate enclosure lies about 200 metres to the north-north-west, making this small rise something of a nucleus for a dense concentration of monuments from different periods.